U.S. Vice President Joe Biden has urged Ukrainian President Petro Poroshenko to quickly reestablish a unified government and carry out reforms sought by the West.

The need to move quickly to quell a political crisis in the wake of the resignation last week of Ukrainian Economy Minister Aivaras Abromavicius, who cited corruption within the government, was discussed in a phone call between the two leaders on February 11, the White House said.

The conversation came one day after Poroshenko talked with International Monetary Fund (IMF) Managing Director Christine Lagarde and assured her that he remains committed to economic reform and rooting out corruption despite Abromavicius's charges.

Lagarde had warned that Ukraine's $17.5 billion loan program was at risk unless the government proceeds with reforms linked to the financial aid.

"The vice president urged the governing coalition to quickly establish unity to allow Ukraine to move forward with reforms, in line with the commitments in its IMF program," the White House said.

Biden and Poroshenko also discussed an uptick in violence in eastern Urkaine and "expressed serious concern about the worsening security situation" there, it said.